Alphanumeric character recording apparatus

ABSTRACT

An apparatus utilizing a character generation control system between a source of light and a light-responsive record medium for recording information in the form of letters, numerals, symbols, etc., which must be recorded in well-registered lines of type fonts across the medium. This is accomplished through the use of a vertical array of individually controlled light beams that are swept simultaneously in a horizontal direction across the surface of the record medium. While doing so the beams of the array are selectively turned on or off in accordance with a predetermined set of character generation requirements. Electrooptic light gating elements are associated with an array of light guides, from which the beams emanate, for effecting the desired on-off conditions for generating a line of characters, and electrooptic light beam deflectors are used to direct the beams to a series of horizontal line positions on the medium.

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3.447,855 6/1969 Skinner 350/150 1 lnvenwr J5ePh McNaney 3.512,s70 5/1970 Wilson 350/160 8548 Boulder Drive, La Mesa, Calif. 92014 [211 App. NO. 885,889 Primary Examiner- Kathleen H. Claffy [22] Filed 17, 1969 Assistant Examiner-Horst F. Brauner [45] Patented Nov. 16, 1971 ABSTRACT: An apparatus utilizing a character generation [5 4] ALPHANUMERIC CHARACTER RECORDING control system between a source of light and a light-responsive APPARATUS record medium for recording information in the form of let- 3 Claims, 7 Drawing Figs ters, numerals, symbols, etc which must be recorded in wellregistered lines of type fonts across the medium. This is ac- 52 US. Cl 178/15, compfished though he use of a vertical array of individually 350/96 controlled li ht beams that are swe t simultaneously in a g P [51] h lt. Cl H041 15/34 horizontal direction across the Surface f the record medium [50] Fleld of Search 178/15, 17 while doing so the beams of the array are selectively turned D; 250/199; 350/96 96 161 on or off in accordance with a predetermined set of character generation requirements. Electrooptic light gating elements [56] References Cited are associated with an array of light guides, from which the UNITED STATES PATENTS beams emanate, for effecting the desired on-off conditions for ,973 10/1959 Koelsch .1 95/45 generating a line of characters, and electrooptic light beam 3,503,666 3/1970 Moore 350/96 deflectors are used to direct the beams to a series of horizontal 3,395,994 8/1968 Cuff 65/17 line positions on the medium.

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PATENTEDNBV 16 I9?! SHEET 2 OF 2 PIC-3'6 INVHNTOR.

ALPHANUMERIC CHARACTER RECORDING APPARATUS BACKGROUND OF THE INVENTION The invention relates to alphanumeric character recording apparatus of the type which derives character-shaped images from a light source and which is designed to make recordations on light-responsive record media at high-speed character writing rates. But more particularly the invention relates to the type of apparatus which is capable of meeting graphic arts print quality normally obtained in the use of rather expensive photocomposing machines, and wherein the printing is expected to be produced in straight lines. Although methods and machines for achieving this are well known in the art, the present invention includes certain basically new concepts offering extremely simple and straightforward means for meeting the higher printing standards of the industry.

SUMMARY OF THE INVENTION In effecting certain character recording objectives of this invention I utilize an array of light guides for deriving a series of vertically displaced and independently controlled light beams from an initial light source, which is preferably a LASER light source. The number of light guides used in the array will depend upon the character print quality requirements of a particular recording application. Therefore, this number could range from at least seven guides in such an array to several hundred light guides. Electro-optic control means is associated with each light guide to control the on and off light emission functions of each guide independently so that any of a number of combinations of vertically displaced beams can be emitted at any point in time.

A lens system is used to project each combination of vertically displaced beams to an equal number of vertically displaced positions on the surface of a record medium, such as light-sensitive film, and an electro-optic light beam deflection system for directing each combination of beams to a predetermined horizontally displaced line position, extending across the surface of the medium, will be used in the formation of lines of characters. In the formation of each character each combination of light beams being emitted from the array of guides is made to coincide with a predetermined line position to which the beams will be directed by the deflection system.

Objects of the invention include high-speed means of recording information in the form of letters, numerals, etc., with an inherent capability of recording such information in straight line of type fashion. A further object is to provide simplified means of recording such information, if necessary, to meet the high quality print standards of the graphic arts field.

The invention, however, both as to its originality and method of operation, and additional objects and advantages, will best be understood from the following description when read with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram of a system embodiment of the invention;

FIG. 2 is a drawing, partly sectional, showing one means for deriving a series oflight beams from a primary light source;

FIG. 3 is a diagram exemplifying a line of informational characters to be referred to in a description of the invention;

FIG. 4 is a diagram of another system embodiment of the invention;

FIG. 5 is a drawing, partly sectional, showing another embodiment of a means for deriving a series of beams from the light source;

FIG. 6 is a drawing, partly sectional, showing a modified version of the FIG. 5 embodiment; and

FIG. 7 is an end view of the drawing in FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the system embodiment of FIG. I there is a light source 40 in one end position thereof and a record medium 50 in an opposite end position. Intermediate these two essential parts of the system there is a light guide assembly 41. As illustrated in FIG. 2, this assembly includes an array of light guides 11 to 17 supported in a bonding material to provide a structure 46 having fist and second surfaces 47 and 48 between which the guides 11 to 17 will extend. These light guides are preferably optical fibers of either glass or plastic, each having a light-conducting core and a jacket of light-conducting material which permits light to be conducted therethrough by means of a series of internal light reflections. The core is designed to have an index of refraction of a value which is higher than the index of its surrounding jacket so as to permit the conducting of light by internal light reflections. Such fibers are well known in the art and are available in diameters down to less than 0.001 inch.

The assembly 41 is shown to contain but seven optical fibers or light guides l l to 17, and the operation of the invention will be described using but seven such guides, however, the advantages of using a much greater number will also be explained since this is a real intent of the invention insofar as the recording of graphic arts quality type fonts is concerned.

The assembly 41 is supported along an optical axis 49 in the path of light from the source 40. Upon reaching the surface 47 and therefore the light admitting ends of the light guides, light will be conducted through the guides to light emitting ends in the plane of the surface 48. The light guides are illustrated as being supported close to one another, or side by side, at their light emitting ends, but spaced apart at their light admitting ends. Adjacent the light admitting ends of each guide there is a light gate 1 through 7 for each of the guides 11 through 17. Each of these light gates include a layer of electro-optic material 9 between a light transparent electrode 8 and a layer of light transparent electrically conductive material 10 deposited on the surface 47 of the assembly 41. A source of polarized light is obtained from the source 40, which is preferably a laser light source, and projected toward the surface 47. An optical system 42 may be used to allow the light admitting ends of the light guides at surface 47 to be flooded with light from the source 40, or, a limited size beam may be directed toward the surface 47 and made to illuminate the light admitting ends of the light guides by deflecting the beam quite rapidly over the light admitting ends. The latter may be accomplished by means of an electro-optic light deflector 43, including at least two prisms of electro-optic crystals, such as barium sodium niobate, for example. Upon the application of voltages to opposite surfaces, by means of electrodes 51 and 52, from a voltage source 53 the index of refraction of adjacent prisms of the deflector 43 may be modified to effect the desired scanning and illumination of the light admitting ends of guides 11 through 17.

Light from the source 40 can be polarized, for example, in the direction of the arrow 54, and upon the application of the influence of an electrical potential between an electrode 8 and the electrode 10, the electro-optic crystal material 9 will permit the light polarized in the direction of the arrow to pass, but in the absence of such electrical influence the light so polarized will be blocked from passage. A polarized optical filter 55 is positioned between the light admitting ends of the guides and the crystal material 9 which permits the passage of light when rotated in relation to the polarized direction 54 of the light from the source 40. Passage of light to the admitting ends of the guides, therefore, will occur when an electrical potential is connected between the common electrode 10 and electrodes 8 associated with each of the electrically responsive light gates 1 through 7. A potential across the material 9 adjacent an electrode 8 will efiect a rotation of the plane of the polarization of the light by 90 and thereby permit passage through the optical filter 55.

Following the assembly 41 electro-optic the axis 49 a lens system will project light emanating from the emitting ends of the guides 1 1 through 17 toward the record medium 50. In the path of these light beams there is shown an electro-optic light beam deflection system 45, including at least two prisms of electro-optic crystals, such as barium sodium niobate, for example, or such other materials possessing electro-optic light deflector characteristics which meet the operating requirements of this invention. The system 45 illustrated includes a pair of prismatic beam deflectors of electrically controllable light-refractive material. The prisms 56 and 57 are supported adjacent one another so as to provide at least two adjoining angular surfaces 58 which intersect the axis 49 of the system, and they are provided with electrodes 59 and 60 on opposite surfaces thereof for subjecting such system to the influence of an electrical potential from the source 53. Series of individual beams from the unit 41 will be deflected by the system 45 to a succession of predetermined horizontally displaced line positions across the record medium 50.

In the following description of the invention the diagram of FIG. 3 will be referred to and an understanding of its operation will be provided by referring to the use of mechanical switching of applying voltages to the various components of the system. In actual practice, however, electronic switching of control potentials in response to coded input signals will be used. Referring to FIG. 3, the description given will consider the use of but the seven light guides illustrated and the vertically displaced light beams emanating therefrom will be related to seven vertically related positions of a line of printed information on the medium 50, such as positions a, b, c, d, e, f, g, in FIG. 3. The greater the number of light guides used, of course, will provide character quality accordingly, but the operating principles will remain the same. The horizontally displaced line positions for each series of beams projected can be identified by the line positions indicated in FIG. 3, through 35, for example. In presenting the work PRIMLY a series of light beams will be derived from the unit 41 by applying a voltage to each of the terminals shown in FIG. 2, a, b, c, d, e, f, and g, in relation the common terminal 20. The word may be started at a point 0 of a path 61 to be followed on the medium 50, by applying a predetermined voltage between the terminals 62 and 63 of the system 45, by presenting a first series of beams a, b, c, d, e, f, g, to a line position 0. A second series of beams a and d will then be deflected to a line position 1; a third series of beams a and d will be deflected to a line position 2; a fourth series of beams a and d will be deflected to a line position 3; a fifth series of beams b and c will be deflected to a line position 4; and so on until the word PRIMLY has been presented. Each series of beams will be presented in the order given by applying voltages, 1st to terminals a, b, c, d, e,f, g in combination with a 0 position related voltage to terminals 62-63; 2nd to terminals a,d in combination with a l-position related voltage to terminals 62-63; 3rd to terminals 0, d, in combination with a 2-position related voltage to terminals 62-63, and so on. Each presentation of a particular series of beams will coincide with a predetermined line position to which a series of beams must be directed to record a desired line of informational characters. Upon recording a line of characters the medium 50 will be advanced to a new position in the direction of the arrow 65.

In order to present better quality type font the number of light guide in the unit 41 would be increased to 100, for example, and the number of horizontally displaced positions on the record medium, for the recording of a single character, could be increased to perhaps 100. But the effecting of a succession of beams selection-beam deflection coincidences along a line across the medium 50 would be carried out as set forth in the above example of recording with the invention, but the number oflight gate means 1 through 7 shown in FIG. 2 would be increased to 100. I

There is a number of electro-optic materials that may be used as the light gate means in the assembly 41, including ferroelectric ceramic lead zirconate titanate, however, a desired light gate effect may also be obtained using nematic liquid crystals as the layer 9 material. But in FIG. 4, still another light gate means will prove desirable which uses electrically controlled material means for allowing, or preventing, the passage of light through a light guide, or optical fiber. System components and their operation is like that described in connection with the FIG. 1 embodiment, however, the operation of the light gate assembly 70 differs somewhat from the assembly 41.

The assembly 70 can be described as containing a similar array of light guides, 71 through 77, and light will be derived from the light emitting ends thereof in response to the application of voltages to a similar set of input terminals a, b, c, d, e, f, g, in relation to a common terminal 20. And these voltages will be applied to coincide with those applied to the terminals 62 and 63 of the deflector system 45 to effect informational character displays as described in connection with the illustration of FIG. 3. Referring to FIGS. 5 and 7, the array of guides 71 to 77 are of glass supported in an air environment 90, the light emitting ends held in position by a support member 98, and adjacent the light admitting ends each guide is provided with means for controlling the passage of light through their entire length. As shown in FIG. 7, the guides are embedded in a material 78 and in FIG. 5 the material 78 is shown to extend along a predetermined length of the guides. Material 78 is a crystal of the electro-optic variety having a predetermined index of refraction, but upon subjecting it to the influence of an electrical potential its particular index of refraction can be made to increase to a higher numerical value. To utilize this characteristic the light guides embedded therein will be designed to have an index higher than the undisturbed predetermined index of the material 78, whereby the lower index of the latter will permit light to be conducted therethrough by means of a series of internal light reflections. Then, upon subjecting the material to the influence of an electrical potential, the index of the material 78 will be made higher than that of the light guide material. Under these latter conditions internal reflections will not take place and, consequently, light admitted to a light guide will not reach its particular light emitting end. To exemplify the operation further, the individual guides will have a diameter of 0.001 inch, or more if required, and the overall thickness of the material 78, indicated at T, might not exceed 0.003 inch.

On opposing surfaces of the material, and adjacent each one of the light guides 71 to 77, there is a pair of electrodes, 81 and 91, 82 and 92, and so on, essentially sandwiching each material 78 clad guides, 71 through 77, between pairs of electrodes, 81-91 through 87-97. The material 78 may be of a number of available electrically controllable light-refractive material, such as electro-optic crystals of barium strontium niobate, barium sodium niobate, KDP, or other materials or means which will provide a change in the index of refraction thereof when subjected to the influence of an electrical field. The electrodes 81 through 87 and 91 through 97 are layers of electrically conducting material capable of absorbing light being reflected thereto. Therefore, when a voltage is applied to one or more of the terminals a through g, in relation to the terminal 20, the index of the material 78 will be made higher than an associated light guide, 71 through 77 causing light not to be reflected through the guide, but, away from the guide and through the material 78 to be absorbed by the adjacent electrode material. In this manner the assembly 70 functions as a multiple light gate unit and will be operated in the same manner as that described in connection with the assembly 41 in FIG. 1 so as to provide a recording of informational characters shown in FIG. 3, for example.

FIG. 6 shows the material 78 extending the full length of the guides 81 through 87, and moreover, grouped together at the light admitting ends 99. In doing so, a smaller beam of light from the source 40 can be used to flood the closely grouped guides. Otherwise, its operation will be like that of FIG. 5, which can still be flooded by a larger area beam, or rapidly scanned by a smaller beam through the use of a deflector 51 and described in connection with the FIG. 1 embodiment.

The particular embodiments of the invention illustrated and described herein is illustrative only, and the invention includes such other modifications and equivalents as may readily appear to those skilled in the arts, and within the scope of the appended claims.

I claim:

A device for electrically controlling the passage of light from a light admitting end to a light emitting end thereof, and the passage of light from said admitting end to light-absorbing material within said device so as to prevent said passage of light to said light emitting end, comprising:

first and second electrodes and said light-absorbing material disposed on opposite sides of said device;

. means for extending means for applying a potential field between said electrodes of an electrical potential between said electrodes;

. said electrodes each having a longitudinal dimension and supported adjacent one another so as to provide intermediate thereof a space extending the length of said longitudinal dimension;

. first lightconducting material, presenting an electrically verse of said longitudinal dimension thereof which is less than, and coincident with, said predetermined cross-sectional dimension of said first material;

. said first material presenting a first index of refraction which is less than said predetermined index and in accordance with the extending of said first influence between said electrodes for reflecting light upon entering the first end of said second material toward the second end thereof, and said first material presenting a second index of refraction which is greater than said predetermined index and in accordance with the extending of said second influence between said electrodes for conducting light upon entering the first end of said second material toward said light-absorbing material and thereby preventing the reflecting of said light toward the second end of said second material.

2. The invention as set forth in claim 1 additionally includg. a plurality of said individual conductors of light within said first material and intermediate, respectively, a plurality of said electrodes; and

h. means for establishing said first index of refraction in the 3. The invention as set forth in claim 2 additionally includi. a light-responsive medium; and j. means for exposing said medium to light being reflected toward said second end of an individual conductor of light.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION $621,138 November 16, 1971 Patent No. Dated Inventor(s) Joseph T. McNaney It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Cancel claims 1, 2 and 3 of the patent and insert claims 1, 2 and 3 of the attached sheets.

Signed and sealed this 9th day of April 1974.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. C. MARSHALL DANN Attesting Officer Commissioner of Patents pomso ($59) USCOMM-DC man-Pu U15. GOVERNHEHT PRINTING OFFICE t... 0-"6-334.

Patent No. 3,621,138 November 16, 1974 Page 2 Claim 1.

A device for electrically controlling the passage of light from a light admitting end to a light emitting end thereof and the passage of light from said admitting end to light absorbing material within said device so as to prevent said passage of light to said light emitting end, comprising:

(a) first and second electrodes, each including an electrically conducting material and a light absorbing material, disposed on opposite sides of said device;

(b) means for applying a potential field between said electrodes;

(0) said electrodes positioned at, and coinciding with each other on, opposite sides of said device so as to provide intermediate said electrodes a space extending along a dimension thereof in the direction of the passage of light from said admitting end to said emitting end of the device;

(d) first light conducting material, presenting an electrically controllable index of refraction, sandwiched between said electrodes in said space having a predetermined cross sectional dimension transverse of said direction of the passage of light through said device;

Patent No 3 ,621 ,138 November 16, 1971 Page 3 (e) second light conducting material, presenting a predetermined index of refraction, first and second ends, and an outer surface along a dimension thereof, said dimension being in said direction of the passage of light through said device, said second light conducting material embedded in said first material along said dimension thereof and thereby included in said sandwich between said electrodes, said second material being in the form of an transverse of the dimension of said outer surface which is less than, and coincident with, said predetermined cross sectional dimension of said first material:

(f) said first material presenting a first index of refraction which is less than said predetermined index and in accordance with the applying of a first potential field between said electrodes for reflecting light upon entering the first end of said second material toward the second end thereof, and said first material presenting a second index of refraction which is greater than said predetermined index and in accordance with the applying of a second potential field between said electrodes for conducting light upon entering the first end of said second material toward said light absorbing material and thereby preventing the reflecting of said light toward the second end of said second material,

Patent No 3,621,138 November 16 1971 Page 4 Claim 2.

The invention as set forth in claim 1 additionally including:

(a) a plurality of said individual conductors of light embedded in said first material along said dimension thereof and intermediate, respectively, a plurality of said electrodes; and

(b) means for establishing said first index of refraction in the first material adjacent one of said plurality of individual conductors simultaneously with the establishing of said second index of refraction in the first material adjacent another of said plurality of individual conductors.

Claim 3,

The invention as set forth in claim 2 additionally including:

(a) a light responsive medium: and

(b) means for exposing said medium to light being reflected through an individual conductor of light and toward said second end thereof upon the applying of a first potential field between said electrodes. 

1. A device for electrically controlling the passage of light from a light admitting end to a light emitting end thereof, and, the passage of light from said admitting end to light-absorbing material within said device so as to prevent said passage of light to said light emitting end, comprising: a. first and second electrodes and said light-absorbing material disposed on opposite sides of said device; b. means for extending means for applying a potential field between said electrodes of an electrical potential between said electrodes; c. said electrodes each having a longitudinal dimension and supported adjacent one another so as to provide intermediate thereof a space extending the length of said longitudinal dimension; d. first light-conducting material, presenting an electrically controllable index of refraction, sandwiched between said electrodes in said space having a predetermined cross-sectional dimension transverse of said longitudinal dimension; e. second light-conducting material, presenting a predetermined index of refraction, first and second ends and an outer surface along a longitudinal dimension thereof, said second lightconducting material embedded in said first material along said longitudinal dimension and thereby included in said sandwich between said electrodes, said second material being in the form of an individual conducTor of light having a cross-sectional dimension transverse of said longitudinal dimension thereof which is less than, and coincident with, said predetermined cross-sectional dimension of said first material; f. said first material presenting a first index of refraction which is less than said predetermined index and in accordance with the extending of said first influence between said electrodes for reflecting light upon entering the first end of said second material toward the second end thereof, and said first material presenting a second index of refraction which is greater than said predetermined index and in accordance with the extending of said second influence between said electrodes for conducting light upon entering the first end of said second material toward said light-absorbing material and thereby preventing the reflecting of said light toward the second end of said second material.
 2. The invention as set forth in claim 1 additionally including: g. a plurality of said individual conductors of light within said first material and intermediate, respectively, a plurality of said electrodes; and h. means for establishing said first index of refraction in the first material adjacent one of said plurality of individual conductors simultaneously with the establishing of said second index of refraction in the first material adjacent another of said plurality of individual conductors.
 3. The invention as set forth in claim 2 additionally including: i. a light-responsive medium; and j. means for exposing said medium to light being reflected toward said second end of an individual conductor of light. 